"A large percentage of Washington’s gang-affiliated and violent youth spend at least some time in Washington’s juvenile institutions or county detention centers (or both). The multiple problems and aggressive tendencies of these youth can create safety issues inside residential facilities, and can prevent youth from moving beyond detention to more pro-social and productive lives. For these reasons, Washington’s Juvenile Rehabilitation Administration [JRA] commissioned this report to determine which evidence-based practices [EBPs] and promising practices work best for serious juvenile offenders, and what factors need to be considered when implementing best practices" (p. 1). Since a wide range of effective programming for juvenile gang members and/or violent juvenile offenders is examined, this report is important reading for anyone working with this juvenile population. Six parts follow an executive summary: JRA and juvenile justice in Washington State; youth gangs and violent juvenile offenders; evidence-based practices—cognitive-behavioral treatment (CBT) programs, family-focused programs, and other programs; promising practices—multiple services programs, substance abuse treatment programs, mentoring programs, academic and employment programs, staff training programs, and others; key factors for program success; and discussion and conclusions. Appendixes provide; additional information about EBPs covered in Part III; and additional information and resources regarding the promising programs described in Part IV.